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In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells
Published on: September 28, 2017
A circadian clock in HaCaT keratinocytes
Florian Spörl1, Katja Schellenberg, Thomas Blatt
1Research and Development, Beiersdorf AG, Hamburg, Germany.
The Journal of Investigative Dermatology
|October 22, 2010
Summary
Scientists discovered a functional circadian clock within skin cells (HaCaT keratinocytes), revealing temperature as a key environmental cue. This finding advances understanding of skin physiology regulation by internal biological rhythms.
Area of Science:
- Chronobiology
- Dermatology
- Molecular Biology
Background:
- Organisms utilize circadian clocks for daily environmental adaptation.
- Skin functions exhibit time-dependent variations, but a local clock in keratinocytes was unconfirmed.
- The molecular link between circadian systems and skin physiology remained unclear.
Purpose of the Study:
- To investigate the presence and function of a cell-autonomous circadian clock in human keratinocytes.
- To identify environmental cues that regulate this epidermal clock.
- To explore the implications for skin physiology.
Main Methods:
- Utilized live-cell bioluminescence imaging and mRNA expression time series in HaCaT keratinocytes.
- Performed genetic and pharmacological perturbation experiments on clock genes.
- Investigated the effects of temperature cycles as a Zeitgeber.
Main Results:
- Demonstrated robust circadian transcription of canonical clock genes in HaCaT keratinocytes.
- Confirmed the molecular similarity of the keratinocyte clock to other peripheral clocks.
- Identified temperature cycles as a potent entrainment cue, revealing rhythmic expression of genes involved in cholesterol homeostasis and differentiation.
Conclusions:
- Established HaCaT keratinocytes as a model for studying circadian regulation of skin physiology.
- Highlighted the role of temperature as a Zeitgeber for epidermal circadian rhythms.
- Provided a molecular basis for understanding daytime-dependent skin functions.
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